Information on Chesapeake Bay Retriever Genetics, Health, and Pedigrees

Exercise Induced Collapse

Exercise Induced Collapse, or EIC, is a neuromuscular condition that causes collapse of dogs when they become overly excited or exercise heavily. A description of an EIC collapse from the University of Minnesota website (used by permission): "The first thing noted is usually a rocking or forced gait. The rear limbs then become weak and unable to support weight. Many affected dogs will continue to run while dragging their back legs. Some of the dogs appear to be in-coordinated, especially in the rear limbs, with a wide-based, long, loose stride rather than the short, stiff strides typically associated with muscle weakness. In some dogs the rear limb collapse progresses to forelimb weakness and occasionally to a total inability to move. Some dogs appear to have a loss of balance and may fall over, particularly as they recover from complete collapse. Most collapsed dogs are totally conscious and alert, still trying to run and retrieve but as many as 25% of affected dogs will appear stunned or disoriented during the episode."

 A collapsing episode typically lasts 5 minutes to a half an hour. Dogs with EIC can overheat rapidly, and in rare cases, some dogs have died during an episode. It is important to monitor a dog carefully during an EIC collapse.

Research into the genetics behind this disorder, which is common in field trial Labrador Retrievers, has been ongoing at the University of Minnesota. Once a gene had been identified by testing many Labradors, the research team at U of MN decided to investigate whether this gene occurred in other breeds. Chesapeake Bay Retrievers participated in the gene prevelance portion of the study, and it was discovered that yes, Chessies do have this gene. There had been occasional reports of Chessies having collapsing episodes, but as these can be caused by many things (such as low thyroid, or overheating), it was not until the gene test was developed that EIC was identified as a condition that Chessies can get. Click here for a listing of dogs that participated in the study, and their results.

EIC is caused by a simple autosomal recessive mutation. This means that a dog must have two copies of the defective gene in order to have EIC. Even so, there are other factors which lead to some dogs collapsing readily, with very little exercise, and others being able to compete at the top level of field trials without ever having an episode. These other factors include environmental ones, such as ambient temperature, or how excited/emotional the dog is at the time. More work is being done to identify these contributing factors, so that those whose dogs test as Affected will know how to manage their dogs in order to avoid any collapsing episodes.

You can test your dog to see if it has EIC or carries the gene, by following the steps listed here. Costs and sample drawing and shipping requirements are located here. Also on this form, you will see information on using the new, cheek swab collection test. This allows owners to test their dogs without having to draw a blood sample. this new sampling option makes it more convenient to get samples from dogs who are at trainers or with handlers, who are very old, or who simply don't like going to the vet! You will need a copy of this information and this form to take to your vet with you if you will be using the blood draw option, or having your vet do the cheek swabs. Be sure to fill the form out completely. Your results will be sent directly to your veterinarian. Once you have received your results from the U of MN, you can certify your dog through OFA. You will need to submit a copy of your test results report from U of MN, plus OFA's Application for DNA Based Genetic Database form. You will send in both the form and the U of MN report, along with the OFA application fee (currently $15) to OFA.

More information about EIC can be found here. The U of MN also has an FAQ on EIC.

If you have further questions about EIC, contact the University of Minnesota at

Two  new articles are presented here, from the University of Minnesota:

U of M Researchers Identify Gene Linked to Common Ailment in Labrador Retrievers

Groundbreaking Discovery Leads to Genetic Test for EIC in Labrador Retrievers